The present invention relates to compositions of activated carbon filtration materials which comprise active carbon composite materials obtained by impregnating inorganic porous bodies with phenolic resins then baking the impregnated bodies thereby carbonizing the resins,
The object of the present invention is to provide activated carbon filtration materials of excellent active carbon sorptive characteristics capable of being in any shape such as pipe, plate or other optional figure for easy use and handling.
For filtration of fine particles or bacilli suspended in liquids, ceramic filter cylinders based on diatomaceous earths are used, and in the case of selective removal of a special solutes from liquids in chemical industry, food industry, pharmaceutical industry and so forth, activated carbon is generally used. However, for filtration and removal of alien substances from distilled water used as medium for medical injection fluid, alcholic drinks, refreshing drinks and other liquids which do not permit the presence of so-called "pyrogen" i.e., fever-generating substances, ceramic filter cylinders are inadequate. Thus physical filtration by specially made filter tubes having capillaries such as around 1 .mu. in radius or sorptive filtration by powdered activated carbon layers, individually or jointly, are employed for the removal. But as neither method is satisfactory there is at present an urgent need for developing more effective filtration materials.
When chemical raw materials and distilled water are processed to manufacture fluids for medical injection the latter are contaminated by various bacilli floating in the ambient air. In other words, there remain in such medical fluids, minute amounts of decomposed substances or bacilli corpses formed by metabolism not completely stopped. These substances are collectively denoted by the general term, "pyrogen," because they produce an extraordinary rise of the body temperature of warm-blooded animals on injection of the contaminated medical fluid. These pyrogens are generally considered to be endotoxins consisting mainly of cell wall phospholipid-polysaccharides of Gram-negative bacilli. Pyrogens are very heat-stable substances not readily destroyed by normal thermal sterilization. While they can be destroyed by a heat treatment of 30 minutes at 250.degree. C, they can not be eliminated by conventional simple filtration methods because such substances have the common property of being easily soluble in water. Accordingly, the pharmaceutical industry is facing difficulties in eliminating them. At present, the industry is employing both high temperature treatment and long-term heat treatment with filtration by filter tubes having minute pores or with sorptive filtration through powdered activated carbon to remove these substances.